ITHACA, New York, April 6, 2010 (ENS) – Red cardinals, blue jays, black crows and robins were among the 10 most sighted birds in this year’s Great Backyard Bird Count, but organizers said one of the most dramatic results from this year’s count was the absence of other bird species.

The Great Backyard Bird Count is a joint project of the National Audubon Society and the Cornell Lab of Ornithology with Canadian partner Bird Studies Canada. It is open to bird watchers of all ages. The results provided a snapshot of the whereabouts of more than 600 bird species.

The 13th annual Great Backyard Bird Count was a record-breaking year for participation. During the four-day event in February, more than 97,200 bird checklists were submitted by an estimated 63,000 volunteer bird watchers from across the United States and Canada.

Northern cardinal (Photo by Betsy Bass in Hampden, Maine)

Checklists came in from all 50 states and from all 10 provinces and three territories of Canada. Participants reported 602 species in 11.2 million individual bird observations.

From reports of rare species to large-scale tracking of bird movements, the Great Backyard Bird Count provides insight into the lives of bird populations.

“The new and the unusual are always a thrill during the Great Backyard Bird Count,” said Robert Petty, western director of field support at Audubon’s division of Education and Centers. “Notable sightings this year included a crimson-collared grosbeak in McAllen, Texas, the first time the species has been reported during the count since 2005.”

“There’s simply no better way to collect information about all these birds so quickly across such a large range,” said Janis Dickinson, citizen science director at the Cornell Lab in Ithaca.

This year, participants recorded more American robins than any other bird species, primarily because of a massive roost in St. Petersburg, Florida. Participants reported 1,450,058 robins in St. Petersburg alone, while birders across the entire rest of the continent tallied 400,321 robins.

At the other extreme, there were few other bird species, including winter finches such as pine siskins and redpolls. Pine siskins moved south in such great numbers last year that they burst onto the Great Backyard Bird Count Top-10 list of most numerous birds for the first time ever, organizers said.

Over time, the Great Backyard Bird Count has recorded dramatic swings in the numbers of these species reported from year to year. These fluctuations may be influenced by the birds’ food supply and reproductive success far to the north. This year, they presumably did not need to travel as far south to find enough food.

Results from this year’s count also documented the continuing expansion of an introduced species across the continent. A dozen years ago, the Eurasian collared-dove was reported in nine states during the bird count. This year more than 14,000 of these doves were reported in 39 states and provinces.

Tree swallows showed dramatic increases in numbers reported compared to years past. Although the number of states reporting the species was down from 25 in 2009 to 20 this year, the number of individuals reported increased nearly four-fold, from 22,431 to 84,585. Whether this is a result of warmer temperatures and earlier migration is not yet clear, organizers said.

Birders off the coast of San Diego were treated to a red-billed tropicbird – the first verified sighting of this species for the Great Backyard Bird Count.

Highlights from Canada included a rustic bunting seen in Creighton, Saskatchewan. In Marathon, Ontario, a gray-crowned rosy finch was a spectacular sighting because it was far outside its normal range in the Rocky Mountains.

“GBBC data become more and more valuable with each passing year,” said Dick Cannings, program director for Bird Studies Canada. “Over time we’ll be better able to see significant changes that may occur in the numbers and distributions of birds which may be tied to climate change, habitat loss, disease, or other factors.”

The Great Backyard Bird Count is sponsored in part by Wild Birds Unlimited. The next Great Backyard Bird Count is February 18-21, 2011.

Top 10 birds reported on the most checklists in the 2010 Great Backyard Bird Count:

Northern Cardinal

Dark-eyed Junco

Mourning Dove

Downy Woodpecker

Blue Jay

American Goldfinch

Tufted Titmouse

House Finch

American Crow

Black-capped Chickadee

Click here to explore the results of the 2010 Great Backyard Bird Count.